what (因为后面的句子提到是一个topic 不是某个人)例如I'm talking about Einstein. - Who are you talking about?I'm talking about geniuses. - What are you talking about?a topic用 what 希望你能够采纳~~...I'm talking about geniuses. - What are you talking about?那天才不也是人吗？为什么说是一个话题？who 一般是用于某个人额。。。。这是理解问题 你记住我说的就好了